Al-Kindi (801-873), Abu Yusuf Yaqub ibn Is-haq ibn as Sabbah ibn ‘omran ibn Ismail Al-Kindi, was one of the highly respected scholars in Dar Al Hekma in multiple fields such as Cryptography, Philosophy, Mathematics, Medicine, Optics, Astronomy, and geography.
His passion towards cryptography in addition to his deep understanding of linguistics, and statistics, led him to think of ways to decipher the encrypted message without knowledge of the secret keys in a reasonable time compared to the typical brute force method. This was the beginning of a new science that is being referred to nowadays as Cryptanalysis.
Al-Kindi documented his conclusions in ‘ Risalah fi Istikhraj al Mu’amma’ book (Treatise on Decrypting Cryptographic Messages), 850 AD, the oldest existing book on cryptology.
To learn more about Al-Kindi’s methodologies in breaking the monoalphabetic substitution cipherduring the Islamic Golden Age, download the full publication by clicking on the link below: